Radiation-curable composition for use in rapid prototyping or rapid manufacturing methods

ABSTRACT

A polymerisable radiation-curable composition comprising:(i) monomers, comprising at least (a) a first monomer having a TG (glass-transition point) of the homopolymer of said first monomer ≥120° C. and at least (b) a second monomer having a TG (glass-transition point) of the homopolymer of the second monomer ≤100° C., wherein at least one of the at least one first monomer or of the at least one second monomer has an alicyclic group, andcomprising (ii) at least one further component, comprising at least one photo-initiator for the UV and/or Vis spectral region or a photo-initiator system for the UV and/or Vis spectral region. Also disclosed is a blank in the form of a three-dimensional moulded body of a polymerised composition, in particular a radiation-cured composition, for producing 3D moulded bodies, dental prosthetic parts, orthopaedic appliances or dental pre-forms in a rapid prototyping, rapid manufacturing, or rapid tooling method.

The invention relates to a polymerisable radiation-curable compositioncomprising

-   (i) monomers, comprising at least (a) a first monomer having a TG    (glass-transition point) of the homopolymer of said first monomer of    greater than or equal to 120° C. and at least (b) a second monomer    having a TG (glass-transition point) of the homopolymer of the    second monomer of less than or equal to 100° C., wherein at least    one of the at least one first monomer or of the at least one second    monomer has an alicyclic group, in particular a bicyclic group, and    optionally at least one di-functional urethane (meth)acrylate    selected from di-functional urethane (meth)acrylates having a    bivalent alkylene group, and comprising (ii) at least one further    component, comprising at least one photo-initiator for the UV and/or    Vis spectral region or a photo-initiator system for the UV and/or    Vis spectral region. Moreover, the invention relates to a blank in    the form of a three-dimensional moulded body of a polymerised    composition, in particular of a radiation-cured composition, for    producing 3D moulded bodies, such as dental models, dental    prosthetic parts, orthopaedic appliances or dental pre-forms, and    also to the use of the composition for producing dental prosthetic    parts, orthopaedic appliances or dental pre-forms in a rapid    prototyping or in a rapid manufacturing or rapid tooling method.

Digital manufacturing methods such as subtractive or additive processes(material build-up processes) are becoming increasingly important indental field in addition to manual manufacturing methods. The advantageof additive processes is saving of expensive raw materials and fasterproduction of the objects. Generative methods are already known indental field e.g. in the form of laser sintering from CoCr, Ti orpolymers for producing crowns and bridges, implant components or models.

Compositions of acrylates or derivatives of acrylates for producingdental restorations having an appropriate characteristics profile inrespect of the mechanical requirements in dental field according to DINEN ISO 207952 are not obtainable up to now (see Quintessenz Zahntech.2017-43(10): page 1325). There is thus a general need for materials forproducing anatomical models, anatomical table-top models and inparticular for producing anatomical models as substitute of the dentalplaster model of the dentition, being produced from the impression ofthe dental situation and the gingiva or the dentition, respectively, ofa patient, or for producing prosthetic parts or definitive dentalrestorations. Furthermore, there is thus a need for compositions forproducing definitive prosthetic parts, orthopaedic appliances or dentalpre-forms.

The impression and the model, here also referred to as anatomical modelor working model form the basis for custom-fit prosthetic restorations.Only if dentist and dental technician adhere to the material-specificrequirements during impression taking and model production you willreceive an individualised optimal restoration.

Usually, the dental technician uses plaster for model production. It iseasy to use and meets the requirements of precise, dimensionally stable,surface-smooth models. The requirements for dental anatomical plastermodels are given below: volume stability, lowest expansion, nocontraction, storage stability, compatible with disinfectants,insulating agents and waxes, a smooth and non-porous surface, sufficientpressure resistance, high edge stability, good abrasion resistance, highthermal capacity, in particular in case of wax extraction, inconjunction with or without water.

It was the object of the present invention to provide a compositionhaving good radiation-curable properties, in particular UV and/or Visradiation-curable properties, with good polymerisation depth inradiation curing. Moreover, the radiation-cured compositions should havegood mechanical properties at both ambient room temperature and alsoelevated temperature, in order to be used in the production ofanatomical models, in particular dental models. The compositions shouldthus meet the requirement of model materials, for producing models formodel casting, implantology, saw cut, and master models, as well asprecise counter-bite models. Therefore, it was the object to provideradiation curable compositions, usable in additive/generative processes,that, as a printed 3D moulded body in cured state, meet the followingrequirements: Maintaining the mechanical properties and dimensionalstability at temperatures of 45° C. to 55° C. in the pressure pot,dimensional stability in thermoforming process, as well as also incleaning e.g. using a steam jet device, storage stability of thelight-curing composition without significant viscosity changes over thestorage period, sufficient reactivity when being irradiated using laser,LED or DLP projector, work pieces/moulded bodies being printable withsufficient geometrical precision/resolution, colour stability of themixture, and no or only a few thixotropy. It was thus the object of theinvention to provide a radiation-curable composition, having, when beingtested in water at 55° C. in polymerised state, a flexural strength ofat least 40 MPa and a flexural modulus synonymous to E-modulus of atleast 800 MPa.

Further requirements for a dental plaster model in several working stepsare outlined below: model in conjunction with thermal impacts and water:Casting-on of plastic saddle in model casting (20 min. at 55° C. in awater bath), completing a partial prosthesis/model casting (20-30 min.at 55° C. in a water bath), completing a total prosthesis (injectiontechnique Palajet/cuvette technique—30 min. at 55° C. in a water bath),completing a total prosthesis tamping-pressing technique (30-40 min. at100° C. in a water bath), thermoforming trays (20-30 min. at 55° C.),water vapour for cleaning (70° C.-110° C.), extracting (3-5 min. at 80°C.-100° C.), veneering with Pala Veneers (55° C., 2 bar, 20 min.).

Model in conjunction with insulations and mechanical impacts:in-articulating, i.e. the model is mechanically loaded in anarticulator, insulation against prosthesis plastic, insulation againstveneering composite, insulation against wax, out-blockability with UVplastic and/or waxes, dipping wax.

Model in conjunction with thermal impacts without water: thermoforming(155-170° C./1 to 2 minutes), hot glue gun to fix the models, gluing waxto fix the models, out-blockability with UV plastic and/or wax, dippingwax, thermoforming foil and manual curing of composites in HiLitePower/3D (twice 90 sec. each and once 180 sec.), curing of occlusalsplints in HiLite Power/3D (twice 5 min. each), milling stump formilling technique (temperature-resistant against accumulated heat).

Behaviour of the polymerised composition in other working steps:dimensionally stable and good cleaning properties in an ultrasonic bathwith isopropanol, discoloration and cleaning in case of articulationfoil (Bausch, red, blue, black), discoloration and cleaning in case ofocclusion spray (several manufacturers), abrasion resistance at thepreparation margin (crowns, bridges, model casting clamping teeth),break/abrasion resistant (in the articulator—plaster against plastic;plastic against plastic).

Situation models and all working models are the basis for all furtherdental technical work. In order to meet high aesthetic requirements,resin compositions for definitive dental restorations, such as e.g. workmodels, orthodontic models must have dimensional stability and thermalstability. If one wants to replace plaster models with printed plasticmodels in order to obtain the advantages of the digital workflow, theplastic models must have the same positive properties as plasters.However, due to various physical and chemical boundary conditions,plastics are subject to thermal plasticity, which must be kept withinlimits by an optimal selection of the monomers.

So far, there are no materials having all thermostable propertiesmentioned, so they can only be used for some dental applications.

Therefore, it was also an object of the invention to provide acomposition comprising monomers having a particularly hight thermalstability and dimensional stability, to resist the elevated temperatureswhen using the polymerised composition as moulded part in a pressure potas well as in case of thermoforming of occlusal splints. During theproduction of aligners, the elevated temperatures must be resistedseveral times.

The objects of the invention are solved by the composition according toclaim 1 as well as the polymerised composition according to claim 12,and also the blank according to claim 14 and the use according to claim15. Preferred embodiments are disclosed in the dependent claims and indetail in the description.

Subject matter of the invention are polymerisable radiation-curablecompositions comprising (i) monomers, wherein the monomers comprise atleast (a) a first monomer having a TG (glass-transition point) of thehomopolymer of said first monomer of greater than or equal to 120° C.and comprise at least (b) a second monomer having a TG (glass transitionpoint) of the homopolymer of the second monomer of less than or equal to100° C., wherein at least one of the at least one first monomer or theat least one second monomer has an alicyclic group, in particular an atleast bicyclic alicyclic group, and (ii) at least one further component,wherein the at least one further component comprises at least onephoto-initiator for the UV and/or vis spectral region or aphoto-initiator system for the UV and/or Vis spectral region.

The term monomers is understood to mean mixtures of the monomersmentioned, such as i.a. mixtures comprising first monomers and secondmonomers also. First monomers are understood to mean (i) a first monomerand also (ii) mixtures of first monomers and second monomers isunderstood to mean (i) a second monomer and also (ii) mixtures of secondmonomers. The TG is preferably determined by means of DSC.

Particularly preferred compositions have a viscosity at ambient roomtemperature, being suitable for use of the said in generativeradiation-curing methods. Therefore, the compositions preferably have aviscosity of less than 5000 m·Pas. Particularly preferably, theviscosity of the composition at ambient room temperature (approx. 20° C.to 23° C.) is less than or equal to 3000 m·Pas, in particular from 500to less than 2500 m·Pas.

According to a preferred embodiment, the compositions have a mixture offirst and second monomers, wherein the first monomers comprisedi-functional acrylates having a bivalent alicyclic group anddi-functional methacrylates having a bivalent alicyclic group, inparticular bivalent bicyclic acrylates or bivalent bicyclicmethacrylates, preferably each of bivalent tetrahydrodicylcopentadienes,and the second monomers comprise at least one mono-functional acrylatehaving an alicyclic group and/or mono-functional methacrylate having analicyclic group, particularly preferred is a mixture of mono-functionalacrylates having a bicyclic alicyclic group and a di-functional acrylatehaving a bicyclic alicyclic group. Likewise preferred are thecorresponding methacrylates of said monomers.

According to an alternative preferred embodiment, a composition ispreferred comprising as (i) monomers

(a) in particular as at least one first monomer, at least onetriacrylate derived from 1,3,5-tris(hydroxyalkyl) isocyanurate, whereinthe hydroxyalkyl residue each independently comprises 1 to 8 C-atoms andin particular is linear, branched and/or cyclic with 3 to 8 C-atoms, inparticular 1 to 6 C-atoms, preferably 1 to 4 C-atoms, preferably 1 to 3C-atoms, particularly preferred is hydroxyethyl, and optionally(b) di-functional acrylates having a bivalent alicyclic group anddi-functional methacrylates having a bivalent alicyclic group, andoptionally(c) in particular as at least one second monomer, at least onemono-functional acrylate having an alicyclic group and/ormono-functional methacrylate having an alicyclic group.

Optionally, (d) at least one disubstituted 4,4′-di(oxabenzol) dialkylmethane of formula I may be present in the composition as a monomer,preferably as at least one third monomer,

with R¹, R², R⁵ and R⁶ each independently selected from H or C1- toC4-alkyl, and with R³ and R⁴ each bivalent C1- to C4-alkylene, with n=0to 6 and m=0 to 6. The disubstituted 4,4′-di(oxabenzol) dialkyl methaneof formula I is a first or a third monomer depending on the substitutionpattern. It is a third monomer with n and m=2 and R¹, R², R⁵ and R⁶equal to methyl and R⁴ and R³ equal to ethylene. It is a third monomerwith formula I equal to n=2 and m=2 and R¹, R², R⁵ and R⁶ equal tomethyl and R⁴ and R³ equal to ethylene that may be present in the totalcomposition with 0 to 50% by weight.

In this context, the monomer (d) may be a first or a third monomer,depending on the selection of residues R¹ to R⁶ and indices n and m, theTG may be greater than or equal to 120° C., so that it is a firstmonomer. The third monomer has a TG greater than or equal to 100° C. andpreferably less than 120° C., and is preferably used in the totalcomposition from 0 to less than 40% by weight only. The monomer having aTG greater than or equal to 30° C. and less than 50° C. is present inthe total composition from 0 to less than 10% by weight.

Preferably, the composition only comprises from 0 to 7.5% by weight,preferably no significant amounts, preferably merely 0 to 0.05% byweight, at least one acrylic ester having an additional carboxy group,such as at least one acrylic acid ester having at least one additionalanhydride group of carboxy groups and/or at least one derivative of theafore-mentioned acrylic acid ester.

A further preferred embodiment of a composition comprises (i) monomers,comprising (a) at least a first monomer or a mixture of first monomershaving a TG (glass-transition point) of the homopolymer of therespective first monomer of greater than or equal to 120° C., whereinthe first monomer or the mixture of first monomers comprises at leastone diacrylic ester based on a tricyclodecane dialkanol, with alkanolcomprising 1 to 6 C-atoms, or a mixture thereof, and (b) at least onesecond monomer or a mixture of second monomers each having a TG(glass-transition point) of the homopolymer of the respective secondmonomer of less than or equal to 100° C., wherein the second monomer orthe mixture of second monomers comprises at least one mono-functionalacrylic ester based on a tricyclodecane alkanol (synonymous to(octahydro-4,7-methano-1H-indenyl) alkanol), with alkanol comprising 1to 6 C-atoms, or a mixture thereof, and optionally at least onedi-functional urethane (meth)acrylate selected from di-functionalurethane (meth)acrylates having a bivalent alkylene group, whereinoptionally

(i) in the composition are present 15 to 25% by weight mono-functionalacrylic ester based on a tricyclodecane alkanol, with alkanol comprising1 to 6 C-atoms, and optionally 5 to 15% by weight diacrylic ester basedon a tricyclodecane dialkanol, with alkanol comprising 1 to 6 C-atoms,wherein the total composition amounts to 100% by weight, or(ii) 5 to 15% by weight diacrylic ester based on a tricyclodecanedialkanol, with alkanol comprising 1 to 6 C-atoms, and 15 to 25% byweight mono-functional acrylic ester based on a tricyclodecane alkanol,with alkanol comprising 1 to 6 C-atoms, in particular in (ii) with nopresence of triacrylate derived from 1,3,5-tris(hydroxyalkyl)isocyanurate, wherein the total composition amounts to 100% by weight,or(iii) 15 to 45% by weight mixture comprising mono-functional acrylicester based on a tricyclodecane alkanol, with alkanol comprising 1 to 6C-atoms, and diacrylic esters based on a tricyclodecane dialkanol, withalkanol comprising 1 to 6 C-atoms, in particular in (iii) with nopresence of triacrylate derived from 1,3,5-tris(hydroxyalkyl)isocyanurate, wherein the total composition amounts to 100% by weight.

Furthermore, the composition may preferably comprise as at least firstmonomers (a.1) the at least one triacrylate derived from1,3,5-tris(hydroxyalkyl) isocyanurate comprising1,3,5-tris(2-hydroxyethyl) isocyanurate triacrylate,1,3,5-tris(2-hydroxmethyl) isocyanurate triacrylate,1,3,5-tris(2-hydroxyethyl) isocyanurate trimethacrylate,1,3,5-tris(2-hydroxymethyl) isocyanurate trimethacrylate or mixturescontaining at least two of the monomers.

Preferred first monomers comprise (b) and are selected fromtricyclodecane dimethanol diacrylate, tricyclodecane dimethanoldimethacrylate, tricyclodecane diethanol diacrylate, tricyclodecanediethanol dimethacrylate and/or mixtures thereof. The abovetricyclodecane monomers may comprise all structural isomers of themonomers.

Alternative monomers, in particular third monomers, from 0 to less thanor equal to 10% by weight, comprise monomers having a TG greater than orequal to 100° C. and preferably less than 120° C. Thus, the compositionmay further comprise monomers such as (d) at least one disubstituted4,4′-di(oxabenzol) dialkyl methane of formula I with R¹, R², R⁵ and R⁶each independently selected from H or C1-Alkyl, and with R³ and R⁴ eachbivalent C1- to C3-alkylene, in particular C2-alkylene, with n=1 to 6and m=1 to 6. Alternatively preferred are R¹ and R² each methyl, and R⁵and R⁶ the same and selected from H, methyl and ethyl, in particularwith R⁵ and R⁶ the same and selected from H and methyl, and with R³ andR⁴ each independently bivalent ethylene or propylene with n=1 to 6,preferably n=2 to 4, and with m=1 to 6, preferably m=2 to 4, preferablywith n=2 and m=2 or with n=4 and m=4 as well as mixtures thereof.Depending on the height of the respective TG of the specificallysubstituted disubstituted 4,4′-di(oxabenzol) dialkyl methane of formulaI, said monomer may be a first or second or third monomer. Preferably,the composition is free of monomers of formula I, in particular with nand m greater than or equal to 4 or contains them from 0 to less than orequal to 7.5% by weight, based on the total composition.

Some monomers of formula I are given below, partially with their TG:ethoxylated (2)bisphenol-A dimethacrylate (TG 105° C.), ethoxylated(2)bisphenol-A diacrylate, ethoxylated (3)bisphenol-A dimethacrylate (TG115° C.), ethoxylated (3)bisphenol-A diacrylate (TG 67° C.), ethoxylated(4)bisphenol-A dimethacrylate (TG 90° C.), ethoxylated (4)bisphenol-Adiacrylate (TG 60° C.), ethoxylated (10)bisphenol-A dimethacrylate (TG(−1° C.)), ethoxylated (10)bisphenol-A diacrylate (TG 2° C.).

According to an alternative, the second monomer or the mixture of secondmonomers may comprise at least one monomer or a mixture of secondmonomers having a TG of the respective homopolymer of greater than orequal to 30° C., preferably comprised are second monomers having a TG inthe range of greater than or equal to 30° C. to less than or equal to100° C., particularly preferred are second monomers having a TG in therange of greater than or equal to 50° C. to less than or equal to 100°C. Further preferred compositions comprise (i) monomers comprising firstmonomers, second monomers and third monomers as well as the additionalcomponent, preferably comprising at least one UV, Vis or UV-Visstabiliser.

According to an alternative, compositions are comprised in which the (i)monomers are present

-   -   40 to 99.99% by weight of the (a) at least one first monomer or        a mixture of first monomers having a TG (glass-transition point)        of the respective homopolymer of the corresponding first monomer        of greater than or equal to 120° C., and    -   0 to 60% by weight, in particular 0 to 10% by weight, of the (b)        at least one second monomer or a mixture of second monomers        having a TG (glass-transition point) of the respective        homopolymer of the corresponding second monomer of less than or        equal to 100° C.,    -   0.01 to 5% by weight of the at least one further component        comprising at least photo-initiator for the UV and/or Vis        spectral region or a photo-initiator system for the UV and/or        Vis spectral region, and optionally at least one stabiliser for        the UV and/or Vis spectral region, and optionally at least one        pigment and/or dye, as well as further usual additives,        wherein the total composition amounts to 100% by weight, and in        particular, wherein the viscosity of the composition at ambient        room temperature (approx. 20° C. to 23° C.) is less than or        equal to 3000 m·Pas, in particular from 500 to less than 2500        m·Pas.

In further alternative embodiments, a composition may comprise as

-   (i) the first monomer-   (e) at least one di-functional urethane (meth)acrylate, being    selected from di-functional urethane (meth)acrylates having a    bivalent alkylene group, and/or-   (f.1) at least one mono-, tri-, tetra- or multi-functional monomer,    in particular not being a urethane (meth)acrylate, in particular    acrylic esters and/or methacrylic esters of polyethers selected from    diacrylic esters of polyethers, tri-, tetra or multi-functional    methacrylic esters of polyethers, diacrylic esters of polyethers,    tri-, tetra- and/or multi-functional acrylic esters of polyethers.

Preferred are compositions, comprising:

-   (i) the second monomer comprising-   (c) at least one mono-functional acrylate having an alicyclic group    and/or mono-functional methacrylate having an alicyclic group, in    particular selected from (octahydro-4,7-methano-1H-indenyl) methanol    acrylate, (octahydro-4,7-methano-1H-indenyl) methanol methacrylate,    (octahydro-4,7-methano-1H-indenyl) ethanol acrylate and    (octahydro-4,7-methano-1H-indenyl) ethanol methacrylate,-   (f.2) at least one mono-, di- tri-, tetra- or multi-functional    monomer, in particular not being a urethane (meth)acrylate, in    particular acrylic esters and/or methacrylic esters of polyethers    selected from dimethacrylic esters of polyethers, tri-, tetra- or    multi-functional methacrylic esters of polyethers, diacrylic esters    of polyethers, tri-, tetra- and/or multi-functional acrylic esters    of polyethers.

Also suitable are trimethylolpropane triacrylate (TG 60° C.),dipentaerythritol pentaacrylate (TG 90° C.), ethoxylated(4)pentaerythritol tetraacrylate (TG 70° C.) and ethoxylated(4)pentaerythritol tetraacrylate (TG 70° C.). In addition,tri-functional monomers may be selected from, wherein the said arepreferably used in the total composition with 0 to 10% by weight only,in particular with 0.01 to 5% by weight: ethoxylated(20)trimethylolpropane triacrylate (TG −40° C.), ethoxylated(3)trimethylolpropane triacrylate, propoxylated (3)trimethylolpropanetriacrylate, ethoxylated (6)trimethylolpropane triacrylate (TG −10° C.),ethoxylated (9)trimethylolpropane triacrylate (TG −20° C.), propoxylated(3)glyceryl triacrylate (TG 20° C.), ethoxylated (15)trimethylolpropanetriacrylate (TG −30° C.). In this context, the viscosity of thecomposition shall be less than 3000 m·Pas.

Likewise preferred compositions may also comprise (iii) third monomers,in particular from 0 to 15% by weight, optionally from 1 to 10% byweight, in addition to the first monomer, wherein the third monomer maycomprise

-   (f.3) at least one mono-, tri-, tetra- or multi-functional monomer,    in particular not being a urethane (meth)acrylate, in particular    acrylic esters and/or methacrylic esters of polyethers selected from    dimethacrylic esters of polyethers, tri-, tetra- or multi-functional    methacrylic esters of polyethers, diacrylic esters of polyethers,    tri-, tetra- and/or multi-functional acrylic esters of polyethers.

Examples for tetraacrylates, being included with the third monomers:pentaerythritol tetraacrylate (TG 105° C.), ditrimethylol propanetetraacrylate (TG 100° C.).

According to a further alternative embodiment, the composition maycomprise (i) monomers comprising:

-   -   70 to 99.99% by weight, in particular 80 to 99.99% by weight (a)        first monomer or mixture of first monomers having a TG        (glass-transition point) of the respective homopolymer of the        corresponding first monomer of greater than or equal to 120° C.,        wherein the first monomer or the mixture of first monomers        comprises at least one di-functional acrylate having a bivalent        alicyclic group and/or at least one di-functional methacrylate        having a bivalent alicyclic group, and optionally at least one        di-functional urethane (meth)acrylate selected from        di-functional urethane (meth)acrylates having a bivalent        alkylene group, and    -   0 to 30% by weight, in particular 0 to 20% by weight, preferably        1 to 15% by weight, at least (b) a second monomer or a mixture        of second monomers having a TG (glass-transition point) of the        respective homopolymer of the corresponding second monomer of        less than or equal to 100° C., wherein the second monomer or the        mixture of second monomers comprises at least one second monomer        or a mixture of second monomers having a TG of the respective        homopolymer of greater than or equal to 30° C., preferably        comprised are second monomers having a TG in the range of        greater than or equal to 30° C. to less than or equal to 100°        C., particularly preferred are second monomers having a TG in        the range of greater than or equal to 50° C. to less than or        equal to 100° C., in particular mono- and/or di-functional        acrylates and/or methacrylates, preferably of bicyclic,        alicyclic acrylates and/or methacrylates, and optionally    -   0 to 10% by weight of a third monomer having a TG of the        respective homopolymer of greater than 100° C., in particular TG        greater than or equal to 105° C. to less than or equal to 115°        C., in particular less than or equal to 118° C., and    -   0.01 to 5% by weight of the at least one further component        comprising at least one photo-initiator for the UV and/or Vis        spectral region or a photo-initiator system for the UV and/or        Vis spectral region, and optionally at least one stabiliser for        the UV and/or Vis spectral region, and optionally at least one        pigment and/or dye, as well as further usual additives.

Likewise, a composition may comprise

-   -   75 to 99.99% by weight, in particular 80 to 99.99% by        weight, (i) (a) first monomer or mixture of first monomers        having a TG (glass-transition point) of the respective        homopolymer of the corresponding first monomer or of the mixture        of monomers of greater than or equal to 120° C., wherein the        first monomer or the mixture of first monomers comprises at        least one di-functional acrylate having a bivalent alicyclic        group and/or at least one di-functional methacrylate having a        bivalent alicyclic group, and optionally at least one        di-functional urethane (meth)acrylate selected from        di-functional urethane (meth)acrylates having a bivalent        alkylene group, and    -   0 to 25% by weight, in particular 0 to 20% by weight, preferably        1 to 20% by weight, at least (b) a second monomer or a mixture        of second monomers having a TG (glass-transition point) of the        respective homopolymer of the corresponding second monomer of        less than or equal to 100° C., wherein the second monomer or the        mixture of second monomers comprises at least one        mono-functional acrylate having an alicyclic group and/or        mono-functional methacrylate having an alicyclic group, with    -   0.01 to 5% by weight of the at least one further component        comprising at least one photo-initiator for the UV and/or Vis        spectral region or a photo-initiator system for the UV and/or        vis spectral region, and optionally a stabiliser for the UV        and/or Vis spectral region, and optionally at least one pigment        and/or dye, as well as further usual additives, wherein the        total compositions amounts to 100% by weight, and in particular,        wherein the viscosity of the composition at ambient room        temperature (approx. 20° C. to 23° C.) is less than or equal to        3000 m·Pas, in particular from 500 to less than 2500 m·Pas.

In particularly preferred compositions, the first monomer is containedin the composition with 70 to 99.99% by weight, in particular 80 to99.99% by weight, and may comprise a mixture of first monomerscomprising 5 to 50% by weight, in particular 5 to 25% by weight,preferably 5 to 20% by weight as at least one di-functional acrylatehaving a bivalent alicyclic group and/or at least one di-functionalmethacrylate having a bivalent alicyclic group, and optionally 5 to 50%by weight, in particular 5 to 45% by weight, preferably 7.5 to 30% byweight at least one di-functional urethane (meth)acrylate selected fromdi-functional urethane (meth)acrylates having a bivalent alkylene group,based on the total composition. Optionally, further first monomers maybe comprised in the mixture of first monomers.

A further particularly preferred composition comprises (i) monomers andthe (ii) at least one further component, wherein a TG(total) iscalculated from 1/TG(total) of the monomers, wherein 1/TG(total) iscalculated according to the following formula, with

1/TG(total)=w1/TG₍₁₎+w2/TG₍₂₎+w3/TG₍₃₎+optionally w4/TG₍₄₎+optionallyw5/TG₍₅₎+optionally wn/TG_((n)),

with w1, w2, w3, w4, w5 and wn each weight proportion of the respectivemonomer, in particular of the respective first monomer, of therespective second monomer or optionally of the respective third monomer,in the total composition of the at least first and second monomers of100% by weight, with n=6 to 50, wherein TG(total) is greater than orequal to 80° C., in particular greater than or equal to 100° C.,preferably greater than or equal to 120° C., preferably greater than orequal to 170° C., and the viscosity of the composition at ambient roomtemperature (approx. 20° C. to 23° C.) is less than or equal to 3000m·Pas, in particular from 500 to less than 2500 m·Pas.

In this context, (i) the monomers comprise at least (a) one firstmonomer having a TG (glass-transition point) of the homopolymer of saidfirst monomer of greater than or equal to 120° C. and at least (b) onesecond monomer having a TG (glass-transition point) of the homopolymerof the second monomer of less than or equal to 100° C., wherein thesecond monomer or the mixture of second monomers comprises at least onesecond monomer or a mixture of second monomers having a TG of therespective homopolymer of greater than or equal to 30° C., preferablycomprised are second monomers having a TG in the range of greater thanor equal to 30° C. to less than or equal to 100° C., particularlypreferred are second monomers having a TG in the range of greater thanor equal to 50° C. to less than or equal to 100° C., (ii) the at leastone further component comprises at least one photo-initiator for the UVand/or Vis spectral region or a photo-initiator system for the UV and/orVis spectral region.

An embodiment of the invention comprises a polymerised composition, inparticular obtainable by radiation-curing of the composition, whereinthe TG(total) is calculated by 1/TG(total) according to the followingformula, and the (i) monomers are present in the total compositionaccording to the following weight proportions (w1, w2, w3, w4, w5 andwn).

1/TG(total)=w1/TG₍₁₎+w2/TG₍₂₎+w3/TG₍₃₎+optionally w4/TG₍₄₎+optionallyw5/TG₍₅₎+optionally wn/TG_((n)),

with w1, w2, w3, w4, w5 and wn each weight proportion of the monomer inthe total composition of the first and second monomers and optionally ofthe third monomer of 100% by weight, with n=6 to 50, wherein TG amountsto greater than or equal to 100° C., and the polymerised composition hasa flexural strength of greater than or equal to 40 MPa (following DIN ENISO 20795-2), in particular measured in water at 55° C., and/or b) anE-modulus of greater than or equal to 800 MPa (following DIN EN ISO20795-2), in particular measured in water at 55° C.

The glass-transition temperature of co-polymers may be approximated bythe Fox equation, see above and [Bulletin of the American PhysicalSociety 1, 3 Page 123 (1956)].

Semi-crystalline plastics (many usual plastics have a crystalline partof 10 to 80%) possess both a glass-transition temperature, the amorphousphase freezes below which (along with embrittlement), and a meltingtemperature, the crystalline phase dissipates at which. Glass-transitionis not a 1^(st) order phase transition and is thus not linked to anexact temperature as the melting point in case of crystals. The foundvalue systematically varies depending on the time and length scale ormovement mode of the molecular dynamics the measurement method used (seebelow) being sensitive to. Whether a plastic can be used above or belowits glass-transition temperature depends on the type of plastic (it isto be noted that the glass-transition temperature of a plastic increaseswith its cross-linking density, i.e. the glass-transition temperature ofa thermosetting plastic is significantly higher than that of athermoplastic). 1/Tg=w1/Tg₍₁₎+w2/Tg₍₂₎ with w1 and w2 as mass proportionof the respective co-monomers and Tg₍₁₎ and Tg₍₂₎ for the respectiveglass-transition temperature of the homopolymers of monomers 1 and 2. Incase of further co-monomers, further terms (wn/Tg_((n))) are integratedinto the equation. The glass-transition temperatures disclosed may begathered from “polymer handbooks” known by the person skilled in theart, from information of the manufacturer of the monomers. Insofar as noinformation concerning glass-transition temperatures is available, thesaid may be determined by means of DSC, DMS (dynamic mechanicalanalysis), dielectric relaxation spectroscopy or dilatrometry. DSCmeasurement is a usual method for determination of the glass-transitiontemperature of the homopolymers. On that point, the homopolymer isdryed, heated to 120° C., rapidly cooled down to −100° C. andsubsequently heated to 150° C. or higher up to 300° C. with 20°C./minute and the data of the glass-transition temperature aredetermined. The glass-transition temperature is measured as a mean.

Preferred are disubstituted 4,4′-di(oxabenzol) dialkyl methanes offormula I with R¹ and R² each methyl, and R⁵ and R⁶ the same andselected from H, methyl and ethyl, in particular with R⁵ and R⁶ the sameand selected from H and methyl, and with R³ and R⁴ each independentlybivalent ethylene or propylene with n=1 to 6, preferably n=2 to 4, andwith m=1 to 6, preferably m=2 to 4, preferably with n=2 and m=2 or withn=4 and m=4 as well as mixtures thereof.

A preferred at least di-functional monomer, not being a urethane(meth)acrylate, is selected from (b) di-functional acrylates having abivalent alicyclic group and di-functional methacrylates having abivalent alicyclic group. Particularly preferred (b) the said areselected from tricyclodecane dimethanol diacrylate (TCDDA),tricyclodecane dimethanol dimethacrylate, tricyclodecane diethanoldiacrylate, tricyclodecane diethanol dimethacrylate and/or mixturesthereof (partially synonymous to bis(methacryloyloxymethyl)tetrahydrodicyclopentadiene or bis(acryloyloxymethyl)tetrahydrodicyclopentadiene.

Preferably, all monomers (a), (b), (c), (d), (e) and (f.1), (f.2) and/or(f.3) according to the invention have an average molecular weight(weight average) of less than 2000 g/mol, particularly preferably themonomers (a), (b), (d), (e) and (f.1). (f.2) and/or (f.3) have anaverage molecular weight of less than 1000 g/mol.

It is also important for the selection of monomers that theyinterconnect well with the filler optionally used. Usually,polyurethanes, acrylates, polyesters and other monomers do not take agood bond with the fillers used. Therefore, the fillers are usuallysilanised or hydrophobized at the surfaces to improve bonding with themonomers.

If no inorganic fillers may be used in the polymerisable composition dueto the specific dental application, e.g. due to the viscosity aimed ofthe composition, there is the possibility to use dyes or pigments in thecomposition for reflection of the irradiation, in particular diffusereflection or scattering respectively of the incoming irradiation. Dyesare considered as compounds being soluble in the polymerisablecomposition and preferably form a clear solution.

The radiation-curable compositions according to the invention maypreferably be irradiated using a radiation source emitting light in theVis spectral region, particularly preferred are radiation sourcesemitting irradiation from 360 to 750 nm, in particular at approx. 385nm, particularly preferably at approx. 405 nm. Particularly preferably,the composition according to the invention may be irradiated using apolychromatic radiation source, such as a DLP projector, or preferablyusing a monochromatic radiation source, such as a laser projector, inthe Vis spectral region from 380 to 660 nm.

The content of photoinitiator may be reduced in the composition whensaid pigments and/or dyes are added. A content of photoinitiator beingtoo high may result in a so-called “overcuring” of the irradiatedcomposition, inaccuracies and/or geometry changes, so that the dentalparts produced appropriately are not usable.

Use of the optionally usable inorganic fillers, pigments or dyesaccording to the invention leads to even scattering of the radiationsource, in particular of the UV and Vis radiation source, in the monomermatrix of the composition, so that an even curing of the composition isanticipated. Ultimately, the polymerised compositions have higher valuesof fracture work achieved.

The composition according to the invention has the following propertiesa) a flexural strength of greater than or equal to 40 MPa, in particulargreater than or equal to 75 MPa and/or b) an E-modulus of greater thanor equal to 800 MPa, in particular greater than 1500 MPa, in particulargreater than or equal to 2000 MPa following DIN EN ISO 20795-2, inparticular usually at ambient room temperature, preferably 23° C.plus/minus 2° C., preferably from ambient room temperature to (in water)55° C. after irradiation using a radiation source in the Vis spectralregion, in particular from 385 to 405 nm, preferably after irradiationin a stereolithography method and obtaining a polymerised composition,preferably in the form of a blank, 3D moulded part, dental prostheticpart, anatomical model, anatomical table-top model, dental workingmodel, dental full model, dental die model, anatomical or dental saw-cutmodel, in particular situation model, counter-bite model, functionalmodel, Pre-model, repair model, precision model, master model as well asprecise counter-bite model, anatomical models for replacement of thedental plaster model of the dentition, prosthetic parts, orthopaedicappliances or dental pre-forms, as well as optional post-tempering ofthe polymerised composition using a radiation source. Preferably, theradiation-cured composition, in particular as moulded body or blank, hasthe flexural strengths and or E-moduli described below. For definitionof the above dental models see Lehrbuch der Zahntechnik, Band 3,Quintessenz Verlag, A. Hohmann, W. Hielscher, 5. Aufl., 2012.Post-curing or post-tempering, respectively may preferably be carriedout e.g. using a laboratory light device (HiLite Power 3D) or in thelight furnace preferably with a light spectrum of 390-540 nm.

Optionally, the composition may additionally contain as (f.2) at leastone di-functional monomer, not being a urethane acrylate or urethanemethacrylate, at least one polyether diacrylate, such as poly(ethyleneglycol) diacrylate, poly(ethylene glycol) di(alkyl) acrylate,poly(propylene glycol) diacrylate, poly(propylene glycol) di(alkyl)acrylate or a mixture of at least two of the afore-mentioned monomers.Preferred polyether diacrylates may be selected from triethylene glycoldimethacrylate, diethylene glycol dimethacrylate and/or tetraethyleneglycol dimethacrylate. Alternatively or additionally, the compositionmay comprise diacrylates selected from diacrylates selected from decanediol di(meth)acrylate, dodecane diol di(meth)acrylate, hexyl decane dioldi(meth)acrylate, butane diol di(meth)acrylate or mixtures containing atleast one of the acrylates.

The indication in parentheses in the terms (methyl) acrylate or (alkyl)acrylate means that the acrylates may be present as acrylate or methylacrylate as well as alternatively as alkyl acrylate.

Hydroxyethyl acrylate may be used as mono-functional monomer. Likewise,hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropylmethacrylate and/or hydroxyethyl acrylate optionally as mixture of atleast two of the afore-mentioned monomers may be used.

Furthermore, the composition may contain (d) at least one at leastdi-functional urethane (meth)acrylate, being selected from di-functionalurethane (meth)acrylates having a bivalent alkylene group (di-functionalurethane acrylates and/or di-functional urethane methacrylates). Thecontent may amount from 0 to 40% by weight in the total composition,wherein the content preferably amounts from 1 to 35% by weight,preferably from 5 to 35% by weight and preferably is component of theamount of the first monomers of 70 to 99.99% by weight.

The di-functional urethane (meth)acrylate having a bivalent alkylenegroup is preferably selected from linear or branched urethanedimethacrylates functionalised with a bivalent alkylene group,functionalised polyethers having alkylene group(s), such asbis(methacryloxy-2-ethoxycarbonylamino)alkylene,bis(methacryloxy-2-ethoxycarbonylamino)-substituted polyalkylene ethers,preferably 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane, UDMA or HEMA-TDMI, respectively. Preferred is abis(methacryloxy-2-ethoxycarbonylamino)alkylene, wherein alkylenecomprises linear or branched C3 to C20, preferably C3 to C6, such asparticularly preferably an alkylene substituted with methyl groups, suchas HEMA-TMDI. The bivalent alkylene preferably comprises 2,2,4-trimethylhexamethylene and/or 2,4,4-trimethyl hexamethylene.

Optionally, one or more fillers may be contained in the composition,such as a doted silicon dioxide filler, in particular a mixed oxide ofzirconium dioxide and silicon dioxide. Particularly preferred are i.a.agglomerated mixed oxides, comprising 75 to 99% by weight silicondioxide and from 1 to 25% by weight zirconium dioxide, based on thetotal composition of the mixed oxide, in particular the mixed oxidecomprises from 85 to 90% by weight silicon dioxide and 10 to 15% byweight zirconium dioxide, wherein it is further preferred for theprimary particles of the agglomerated oxide particles to comprisemicrocrystalline domains of 4 to 7 nm and for the crystallinity index tobe advantageously 0.6 to 0.7—determined according to the method ofWindisch et al. (WO 01/30306A)—and for the agglomerated oxide particlesto be surface-modified with an organofunctional silane being reactivewith respect to at least one monomer and/or polymer component. Saidagglomerated oxide particles treated according to the invention haveoutstanding properties in abrasion measurements, regarding the glosslevel, an outstanding transparency and very good values in reflexion androughness measurements after a toothbrush test.

The particle sizes of the inorganic fillers, such as of the at least oneinorganic oxide, mixed oxide or dental glass, e.g. comprising bariumaluminium oxide, have an average particle diameter of d₅₀ less than 10μm for the present application, particularly preferably the fillers havea particle diameter of approximately 3 to 70 nm, in particular of 10 to50 nm (nanometers), optionally the particles may be aggregated oragglomerated as particles with up to 10 μm. The primary particles sizesof the inorganic fillers, which may optionally be present asagglomerated and/or aggregated primary particles, have an averageparticle diameter of approximately 3 to 70 nm, in particular of 10 to 50nm. Preferably, the mixed oxides of zirconium dioxide with silicondioxide have a primary particle size of 3 to 70 nm. The advantage of thevery small particle diameters, which may be aggregated and/oragglomerated as appropriate, is that the light is scattered in asubstantially diffuse manner by these particles in case of radiationcuring and thus leads to better curing in stereolithography methods orDLP methods.

Furthermore, it is preferred for the composition to be non-thixotropic.In addition, it is particularly preferred for the composition to have aviscosity of less than 3000 m·Pas, in particular from 500 to less than2500 m·Pas, preferably from 500 to 2000 m·Pas, particularly preferablyfrom 500 to 1600 m·Pas. The viscosity is preferably measured accordingto DIN 1342-2; 2003-11 Newtonian liquids or DIN 1342-3; 2003-11non-Newtonian liquids using a rheometer (Anton Par, Physica MCR 301,viscosity ranges 200-3000 m·Pas at 100/s 23° C.). The compositionsaccording to the invention have no or preferably only a low thixotropy.The compositions produced are structurally viscous, wherein it ispreferred for the compositions to be structurally viscous with andwithout fillers. According to another embodiment, it is preferred ifalmost no changes in viscosity occur over a longer storage period.Furthermore, the compositions have a very good reactivity when beingirradiated using a laser or DLP projector.

Particularly preferred photo-initiators comprise alpha-hydroxyphenylketone, benzil dimethyl ketal or 2,4,6-trimethyl benzoyl diphenylphosphine oxide, phenyl-bis(2,4,6-trimethylbenzoyl) phosphine oxide,2,4,6-trimethyl benzoyl phenyl phosphinic acid ethyl ester, and mixturesof at least two of the photo-initiators, phenyl phosphine oxidecombinations, bisacryl phosphine oxides (BAPO).

Typical stabilisers comprise 2,6-di-tert.-butyl-4-methyl phenol (BHT) orhydroquinone monomethyl ether (MEHQ), 2-hydroxy-4-methoxybenzophenone,HALS (hindered amine light stabilisers), benzotriazole ultravioletabsorbers (UVAs) and hydroxyphenyl triazines (HPT).

According to a further preferred embodiment, the composition maycomprise:

(ii) 0.01 to 2% by weight photo-initiators for the UV and/or Visspectral region or a photo-initiator system for the UV and/or visspectral region, and 0.01 to 2% by weight stabiliser, and optionally (g)0 to 10% by weight, in particular 0.01 to 7.5% by weight inorganicfillers comprising inorganic oxides or inorganic mixed oxides and/ordental glasses, in particular zirconium dioxide, mixed oxides ofzirconium oxide and silicon dioxide, silicon dioxide, wherein the totalcomposition amounts to 100% by weight.

Likewise, a subject matter of the invention are compositions, optionallycomprising fillers having primary particle sizes of the inorganicfillers, optionally being present as agglomerated and/or aggregatedprimary particles, of in average having a particle diameter of circa 3to 70 nm, in particular from 10 bis 50 nm. Alternatively oradditionally, usual fillers having particle sizes of 0.4 to 10 μm may beused in the composition.

Furthermore, a subject matter of the invention is a polymerisedcomposition as well as an appropriate 3D moulded body, as well as alsothe dental models, splints, orthodontic appliances and prostheticmoulded parts or blanks mentioned below, wherein the polymerisedcomposition alternatively or cumulatively has i) a) a flexural strengthof greater than or equal to 75 MPa (following DIN EN ISO 20795-2), inparticular greater than or equal to 80 MPa, preferably greater than orequal to 90 MPa (measured following DIN EN ISO 139) and/or b) anE-modulus of greater than or equal to 2000 MPa (following DIN EN ISO20795-2), and/or

ii) a) a flexural strength of greater than or equal to 70 MPa (followingDIN EN ISO 20795-2), in particular measured in water at 37° C., and/orb) an E-modulus of greater than or equal to 2000 MPa (following DIN ENISO 20795-2), in particular measured in water at 37° C., and/oriii) a) a flexural strength of greater than or equal to 50 MPa(following DIN EN ISO 20795-2), in particular measured in water at 45°C., and/or b) an E-modulus of greater than or equal to 1500 MPa(following DIN EN ISO 20795-2), in particular measured in water at 45°C., and/or iv) a) a flexural strength of greater than or equal to 40 MPa(following DIN EN ISO 20795-2), in particular measured in water at 55°C., and/or b) an E-modulus of greater than or equal to 900 MPa(following DIN EN ISO 20795-2), in particular measured in water at 55°C., in particular being obtainable by irradiation of a polymerisablecomposition.

In this context, it is particularly preferred for the polymerisedcomposition to have a shrinkage of less than 7%, preferably a shrinkageof less than or equal to 6.8%, preferred less than or equal to 6.5%,particularly preferably less than or equal to 6.0% (determined accordingto Watts, Dent. Mater 7: 281-286, Okt. 1991, also referred to as BondedDisc-Method, at ambient room temperature, Translux Energy, 60 slighting).

Furthermore, a subject matter of the invention is a blank in the form ofa three-dimensional moulded body of a polymerised composition suitablefor producing dental prosthetic parts, orthopaedic appliances or dentalpre-forms, wherein the blank has a.1) a flexural strength of greaterthan or equal to 75 MPa (following DIN EN ISO 20795-2) and/or b.1) anE-modulus of greater than or equal to 2000 MPa (following DIN EN ISO20795-2), and optionally a.2) a flexural strength of greater than orequal to 50 MPa (following DIN EN ISO 20795-2), in particular measuredin water at 45° C., and/or b.2) an E-modulus of greater than or equal to1500 MPa (following DIN EN ISO 20795-2), in particular measured in waterat 45° C., and optionally

iv) a) a flexural strength of greater than or equal to 40 MPa (followingDIN EN ISO 20795-2), in particular measured in water at 55° C., and/orb) an E-modulus of greater than or equal to 900 MPa (following DIN ENISO 20795-2), in particular measured in water at 55° C.

Also a subject matter of the invention is the use of a composition forproducing anatomical models, anatomical table-top models, anatomicalmodels for replacement of the dental plaster model of the dentition,prosthetic parts, dental prosthetic parts, orthopaedic appliances,aligners, dental splints, or dental pre-forms, as well as the use of acomposition according to the invention in a rapid prototyping or in arapid manufacturing or rapid tooling method. Preferred is aradiation-curing of the composition by means of laser beams, LED lightsources or DLP projectors.

Furthermore, a subject matter of the invention is the use of acomposition for producing dental prosthetic parts comprising prosthesisbase or parts thereof, artificial teeth, dental arch having at least twoto 16 artificial teeth being interdentally connected in an integralmanner, crowns, provisional crowns, total prostheses, total crowns,splints for orthodontic corrections (similar to Invisalign), dentalbridges, abutments, suprastructures, dental bars, inlays, onlays,orthopaedic appliances, such as occlusal splints, dental pre-forms ofartificial teeth, surgical guides for implantology, mouthguards, and/orimplants.

Presently, dental products are in particular understood to mean dentalproducts being producible from polymerisable compositions, such as e.g.not exhaustive total protheses, provisional crowns and bridges, inlays,onlays, total crowns, occlusal splints, surgical guides forimplantology, splints for orthodontic corrections (similar toInvisalign), mouthguards, artificial teeth.

In order to meet high aesthetic requirements, compositions usable indental field for producing definitive dental restorations, such as e.g.work models, orthodontic models, surgical guides, temporary prosthesesas well as splints, must have a high degree of transparency. Thistransparency is usually achieved by optimal adaption of the refractiveindices of the fillers and the polymer matrix. However, due to variousphysical and chemical boundary conditions, very narrow limits are setfor the selection of both fillers and monomers.

According to a further alternative embodiment, polymerised compositionsor blanks are obtainable, in particular radiation-cured compositions, inparticular UV-Vis-cured compositions, preferably being additionallyradiation-cured from all sides, having the following properties withregard to their flexural strength and/or E-modulus following DIN EN USO20795-2. Additional radiation-curing from all sides is understood tomean post-tempering in 3D light furnace for example.

In this context, the following methods—rapid prototyping or rapidmanufacturing, a method for producing work pieces, such as a dentalprosthetic part, or rapid tooling, a method for producing tools—eachcomprise stereolithography methods and DLP methods. Optionally,post-tempering with UV, Vis or UV-Vis light may be carried out in theafore-mentioned methods after curing of the polymerisable composition.Preferably, post-tempering of the polymerised composition or of thedental prosthetic parts, of the orthopaedic appliances or dentalpre-forms or blanks is carried out concurrently from at least threesides, preferably from five to six sides, as it is possible in a lightfurnace. Alternatively, the polymerised composition may be temperedadditionally or alternatively.

Colour pigments may additionally be added to the composition to adjustthe colour. In addition, red fibres may be added to the composition toimitate blood vessels of the gingiva. Suitable colour pigments are forexample: PV pigment red—CAS 4948-15-6, pigment blue 220943—CAS68186-87-8, pigment black 100—CAS 68186-91-4, Kronos 2220—CAS 13463-67-7and light yellow 3R—CAS 68186-90-3.

Layer thicknesses in the range of 5 μm, in particular from 25 μm to 250μm, per curing layer may be achieved in the polymerised compositions.The printed layers are particularly preferably at 30 μm, 50 μm, 70 μm,100 μm, 120 μm and 170 μm.

High transparency may be achieved by optimal selection of the recipecomponents in respect of their refractive indices.

Benzoin alkyl ethers or esters, benzil monoketales, acylphosphine oxidesor aliphatic and aromatic 1,2-diketo compounds, such as for example2,2-diethoxyacetophenone, 9,10-phenanthrene quinone, diacetyl, furil,anisil, 4,4′-dichlorobenzil and 4,4′-dialkoxybenzil or camphorquinone,are conceivable as photoinitiators for example. The photoinitiators arepreferably used together with a reducing agent. Examples for reducingagents include amines such as aliphatic or aromatic tertiary amines, forexample N,N-dimethyl-p-toluidine or triethanol amine, cyan ethyl methylaniline, triethyl amine, N,N-dimethyl aniline, N-methyl diphenyl amine,N,N-dimethyl-sym.-xylidine, N,N-3,5-tetramethyl aniline and 4-dimethylaminobenzoic acid ethyl ester or organic phosphites. Usualphotoinitiator systems are e.g. camphor quinone plusethyl-4-(N,N-dimethylamino)benzoate,2-(ethylhexyl)-4-(N,N-dimethylamino)benzoate or N,N-dimethyl aminoethylmethacrylate.

2,4,6-trimethyl benzoyl diphenyl phosphine oxide is particularlysuitable as initiator for polymerisation initiated by UV light. UVphoto-initiators may be used alone or in conjunction with an initiatorfor visible light.

Particularly preferred photo-initiators and/or initiator systemscomprise a) at least one radical photo-initiator, in particular at leastone peroxide and/or azo compound, in particular LPO: dilauroyl peroxide,BPO: dibenzoyl peroxide, t-BPEH: tert.-butylper-2-ethyl hexanoate, AIBN:2,2′-azobis-(isobutyronitrile), DTBP: di-tert.-butyl peroxide, or analpha-hydroxy ketone, camphorquinone, acyl phosphine oxide. Optionally,stabilisers may be added additionally and optionally b) at least oneco-initiator such as an amine, usually a tert-amine, in particular atleast one aromatic amine, such as N,N-dimethyl-p-toluidine,N,N-dihydroxyethyl-p-toluidine and/or p-dibenzyl aminobenzoic aciddiethyl ester.

Particularly preferred photo-initiators comprise alpha-hydroxyphenylketone, benzil dimethyl ketal or 2,4,6-trimethyl benzoyl diphenylphosphine oxide, phenyl-bis(2,4,6-trimethylbenzoyl) phosphine oxide,2,4,6-trimethyl benzoyl phenyl phosphinic acid ethyl ester, and mixturesof at least two of the photo-initiators, phenyl phosphine oxidecombinations, bisacryl phosphine oxides (BAPO).

Typical stabilisers comprise 2,6-di-tert.-butyl-4-methyl phenol (BHT) orhydroquinone monomethyl ether (MEHQ), 2-hydroxy-4-methoxybenzophenone,HALS (hindered amine light stabilisers), benzotriazole ultravioletabsorbers (UVAs) and hydroxyphenyl triazines (HPT).

The invention is explained in more detail by the following exampleswithout limiting the invention to these exemplary embodiments.

The composition according to the invention may be used to print workpieces, blanks or three-dimensional moulded bodies having very goodgeometrical precision/resolution. The moulded bodies according to theinvention have very good mechanical properties even at elevatedtemperatures. Furthermore, good colour stability can be observed in thework pieces.

EXEMPLARY EMBODIMENTS

General example of production: the initiators are pre-dissolved in(octahydro-4,7-methano-1H-indenyl)methyl acrylate or tricyclodecanedimethanol diacrylate. Subsequently, the other monomers are added andthe mixture is homogenised. Pigment concentrates or pigments may beadded. The composition is then preferably homogenised. The compositionproduced is processable with a 3D printer. It is to be noted that thelight-sensitive initiators may react to an undesired polymerisation inconnection with the ambient light (the composition is preferablytransferred into the pressure bath under appropriate measures). Lightingis carried out at 385-405 nm and post-curing or post-tempering,respectively, is carried out e.g. with a laboratory light device HiLitePower 3D.

The mixture produced is used to print test specimens according to ISO20795-2 (50 μm) for the following tests on a 3D precision printer havingthe wavelength 405 nm (Cara Print 4.0). The test specimens were washedup with isopropanol after the printing process and subjected to apost-tempering process. The said was carried out by lighting on bothsides in a laboratory light device HiLite Power 3D, 200 W (Kulzer GmbH)for 3 to 5 min respectively or as specified by the manufacturer.Properties of the mixture according to the invention for modellingmaterials, tested according to DIN EN ISO 20795-2 or following the norm,respectively:

TABLE 1 Comparative example TG Functional TG VG1 VG2tris(2-hydroxyethyl) 3 270 17.7 isocyanurate triacrylate ethoxylated (2)bisphenol-A 2 115 30 30 dimethacrylate (octahydro-4,7-methano-1H- 1 3517.7 indenyl) methylacrylate tricyclodecane dimethanol 2 185 10 10diacrylate aliphatic urethane acrylate 2 148 amine-modified polyether 425 35 35 acrylate ethoxylated (4) bisphenol-A 2 60 6 6 diacrylatestabiliser/photo-initiator 0.5 bis 0.5 bis 2.0 2.00 Flexural strength inMPa 35.4 54.2 E-modulus in MPa 1081 1761 Bending fracture in MPa 0.670.47 m^(1/2) ≥ 1.1 Fracture work in J/m² > 250 75.6 33.49

Comparative examples 1 and 2 show a high amount of quad crosslinkersalone does not guarantee for good mechanical properties, as thecomparative examples do not exhibit acceptable mechanical propertieseven at ambient room temperature. Although the compositions of thecomparative examples have a viscosity of good usability for 3D printingapplications, however the requirements for the mechanical propertiesfollowing ISO-20795 are not achieved.

TABLE 2a VG3 and Examples 1 and 2 Compositions VG3 1 2tris(2-hydroxyethyl) isocyanurate triacrylate ethoxAated (2) bisphenol-Adimethacrylate 30 36 42.25 (octahydro-4,7-methano-1H-indenyl) 19.8619.86 19.86 methyl acrylate tricyclodecane dimethanol diacrylate 10 1010 carboxyacrylate* 28.25 6.25 ethoxylated (4) bisphenol-A diacrylate11.25 UDMA 27.25 27.25 Calculated TG 79 107 111 *TG: 39° C.

TABLE 2b Flexural strength and E-modulus Test Compositions StorageTesting VG3 1 2 Storage dry dry Flexural strength in [MPa] 113.3 82 81.3ISO/20795 E-modulus in [MPa] 2880 2494 2319 Storage dry in waterFlexural strength in [MPa] 68.7 76.6 63.2 ISO/20795 (37° C.) E-modulusin [MPa] 2131 2012 1797 Storage dry in water Flexural strength in [MPa]45.6 59.2 55.7 ISO/20795 (45° C.) E-modulus in [MPa] 1329 1624 1528Storage dry in water Flexural strength in [MPa] 21.1 46.8 43.9 ISO/20795(55° C.) E-modulus in [MPa] kein 1121 987

TABLE 3a Examples 3 to 6 Compositions 3 4 5 6 tris(2-hydroxyethyl)isocyanurate triacrylate 13.34 11 10 12 ethoxylated (2) bisphenol-Adimethacrylate 40 40 45 40 (octahydro-4,7-methano-1H-indenyl) methyl13.34 11 10 12 acrylate tricyclodecane dimethanol diacrylate 13.34 11 1012 Carboxyacrylate ethoxylated (4) bisphenol-A diacrylate UDMA 17.8 24.722.7 22 Calculated TG 137 135.5 133 130

TABLE 3b Examples 3 to 6 Mechanics following Storage Prüfung ISO-20795 34 5 6 Storage dry dry Flexural strength 85.5 93 105.5 104.3 ISO/20795 in[MPa] E-modulus in 2592 2841 2883 2726 [MPa] Storage dry in waterFlexural strength 72.2 87.5 88.1 84.5 ISO/20795 (37° C.) in [MPa]E-modulus in 2134 2447 2344 2264 [MPa] Storage dry in water Flexuralstrength 62.1 65.1 70.6 68.5 ISO/20795 (45° C.) in [MPa] E-modulus in1799 1831 1958 1813 [MPa] Storage dry in water Flexural strength 45.858.2 54.8 51.1 ISO/20795 (55° C.) in [MPa] E-modulus in 1120 1428 13461194 [MPa]

TABLE 4a Thermostability of compositions according to the inventionBeispiel 7 Beispiel 8 Beispiel 9 Calculated TG 135 186 201Thermostability Mechanics following Storage Testing ISO-20795 Storagedry Flexural strength 84.2 90.6 95.3 dry in [MPa] E-modulus in 2615 27852859 [MPa] Storage in water Flexural strength 81.2 71 79.4 dry (37° C.)in [MPa] E-modulus in 2185 2316 2412 [MPa] Storage in water Flexuralstrength 58.2 66.4 75.7 dry (45° C.) in [MPa] E-modulus in 1559 18891993 [MPa] Storage in water Flexural strength 44.9 59.3 60.2 dry (55°C.) in [MPa] E-modulus in 940 1485 1582 [MPa] Shrinkage [%] 5.5 6.416.76 according to Watts Viscosity 1390 1560 2224 [m · Pas]

TABLE 4b Compositions according to the invention Example 7 Example 8Example 9 135° C. 186° C. 201° C. Calculated TG Amount in Amount inAmount in Monomers TG % by weight % by weight % by weight aliphaticurethane dimethacrylate 148 27.7 32.5 ethoxylated (2) bisphenol-A 105 4032.5 dimethacrylate tris(2-hydroxyethyl) isocyanurate 270 10 32.5 32.5triacrylate (octahydro-4,7-methano-1H- 35 10 indenyl) methylacrylatetricyclodecane dimethanol 185 10 32.5 32.5 diacrylate

1. Polymerisable radiation-curable composition comprising (i) monomersand (ii) at least one further component, wherein in the composition arepresent (i) 40 to 99.99% by weight (a) at least one first monomer or amixture of first monomers having a TG (glass-transition point) of therespective homopolymer of the corresponding first monomer of greaterthan or equal to 120° C., and as at least one first monomer at least onetriacrylate derived from 1,3,5-tris(hydroxyalkyl) isocyanurate, whereinthe hydroxyalkyl residue each independently comprises 1 to 8 C-atoms,and optionally comprises di-functional acrylates having a bivalentalicyclic group and/or di-functional methacrylates having a bivalentalicyclic group, and 0 to 60% by weight (b) at least one second monomeror a mixture of second monomers having a TG (glass-transition point) ofthe respective homopolymer of the corresponding second monomer of lessthan or equal to 100° C., and (ii) 0.01 to 5% by weight of the at leastone further component comprising at least one photo-initiator for the UVand/or Vis spectral region or a photo-initiator system for the UV and/orVis spectral region, and optionally at least one stabiliser for the UVand/or Vis spectral region, and optionally at least one pigment and/ordye as well as further additives, wherein the total composition amountsto 100% by weight, and wherein the viscosity of the composition atambient room temperature (approx. 20° C. to 23° C.) is less than orequal to 3000 m·Pas.
 2. Composition according to claim 1, wherein theviscosity of the composition at ambient room temperature (approx. 20° C.to 23° C.) from 500 to less than 2500 m·Pas.
 3. Composition according toclaim 1, wherein (i) the monomers comprise at least one triacrylatederived from 1,3,5-tris(hydroxyalkyl) isocyanurate, wherein thehydroxyalkyl residue each independently comprises 1 to 8 C-atoms, andoptionally di functional acrylates having a bivalent alicyclic group anddi-functional methacrylates having a bivalent alicyclic group, andoptionally at least one mono-functional acrylate having an alicyclicgroup and/or mono-functional methacrylate having an alicyclic group. 4.Composition according to claim 3, wherein (i) the monomers comprise (a)at least one first monomer or a mixture of first monomers having a TG(glass-transition point) of the homopolymer of the respective firstmonomer of greater than or equal to 120° C., wherein the first monomeror the mixture of first monomers comprises at least one diacrylic esterbeing based on a tricyclodecane dialkanol, with alkanol comprising 1 to6 C-atoms, or a mixture thereof, and (b) at least one second monomer ora mixture of second monomers each having a TG (glass-transition point)of the homopolymer of the respective second monomer of less than orequal to 100° C., wherein the second monomer or the mixture of secondmonomers comprises at least one mono-functional acrylic ester beingbased on a tricyclodecane alkanol, with alkanol comprising 1 to 6C-atoms, or a mixture thereof, and optionally at least one di-functionalurethane (meth)acrylate selected from di-functional urethane(meth)acrylates having a bivalent alkylene group.
 5. (canceled) 6.Composition according to claim 1, wherein (14a) is selected fromtricyclodecane dimethanol diacrylate, tricyclodecane dimethanoldimethacrylate, tricyclodecane diethanol diacrylate, tricyclodecanediethanol dimethacrylate and/or mixtures thereof.
 7. Compositionaccording to claim 4, wherein (i) the first monomer comprises (e) atleast one di-functional urethane (meth)acrylate selected fromdi-functional urethane (meth)acrylates having a bivalent alkylene group,and/or (f.1) at least one mono-, tri-, tetra- or multi-functionalmonomer, being acrylic esters and/or methacrylic esters of polyethersselected from di-methacrylic esters of polyethers, tri-, tetra- ormulti-functional methacrylic esters of polyethers, diacrylic esters ofpolyethers, tri-, tetra- and/or multi-functional acrylic esters ofpolyethers.
 8. Composition according to claim 4, wherein (i) the secondmonomer comprises (c) at least one mono-functional acrylate having analicyclic group and/or mono-functional methacrylate having an alicyclicgroup, selected from (octahydro-4,7-methano-1H-indenyl) methanolacrylate, (octahydro-4,7-methano-1H-indenyl) methanol methacrylate,(octahydro-4,7-methano-1H-indenyl) ethanol acrylate and(octahydro-4,7-methano-1H-indenyl) ethanol methacrylate, (f.2) at leastone mono-, tri-, tetra- or multi-functional monomer, being acrylicesters and/or methacrylic esters of polyethers selected fromdimethacrylic esters of polyethers, tri-, tetra- or multi-functionalmethacrylic esters of polyethers, diacrylic esters of polyethers, tri-,tetra- and/or multi-functional acrylic esters of polyethers. 9.Composition according to claim 1, wherein there are in the composition(i) monomers comprising 70 to 99.99% by weight (a) first monomer ormixture of first monomers having a TG (glass-transition point) of therespective homopolymer of the corresponding first monomer of greaterthan or equal to 120° C., wherein the first monomer or the mixture offirst monomers comprises at least one di-functional acrylate having abivalent alicyclic group and/or at least one di-functional methacrylatehaving a bivalent alicyclic group, and optionally at least onedi-functional urethane (meth)acrylate selected from di-functionalurethane (meth)acrylates having a bivalent alkylene group, and 0 to 30%by weight at least (b) one second monomer or a mixture of secondmonomers having a TG (glass-transition point) of the respectivehomopolymer of the corresponding second monomer of less than or equal to100° C., wherein the second monomer or the mixture of second monomercomprises at least one monomer or a mixture of second monomers having aTG of the respective homopolymer of greater than or equal to 30° C., and0.01 to 5% by weight of the at least one further component comprising atleast one photo-initiator for the UV and/or Vis spectral region or aphoto-initiator system for the UV and/or Vis spectral region, andoptionally at least one stabiliser for the UV and/or Vis spectralregion, and optionally at least one pigment and/or dye as well asfurther usual additives, wherein the total compositions amounts to 100%by weight.
 10. Composition according to claim 1, wherein there are inthe composition (i) monomers comprising 75 to 99.99% by weight (a) firstmonomer or mixture of first monomers having a TG (glass-transitionpoint) of the respective homopolymer of the corresponding first monomeror the mixture of first monomers of greater than or equal to 120° C.,wherein the first monomer or the mixture of first monomers comprises atleast one di-functional acrylate having a bivalent alicyclic groupand/or at least one di-functional methacrylate having a bivalentalicyclic group, and optionally at least one di-functional urethane(meth)acrylate selected from di-functional urethane (meth)acrylateshaving a bivalent alkylene group, and 0 to 25% by weight at least (b)one second monomer or a mixture of second monomers having a TG(glass-transition point) of the respective homopolymer of thecorresponding second monomer of less than or equal to 100° C., whereinthe second monomer or the mixture of second monomers comprises at leastone mono-functional acrylate having an alicyclic group and/ormono-functional methacrylate having an alicyclic group, with 0.01 to 5%by weight of the at least one further component comprising at least onephoto-initiator for the UV and/or Vis spectral region or aphoto-initiator system for the UV and/or Vis spectral region, andoptionally at least one stabiliser for the UV and/or Vis spectralregion, and optionally at least one pigment and/or dye as well asfurther usual additives. wherein the total composition amounts to 100%by weight, and wherein the viscosity of the composition at ambient roomtemperature (approx. 20° C. to 23° C.) is less than or equal to 3000m·Pas.
 11. Composition according to claim 1, wherein the (i) monomersand the (ii) at least one further component are present in thecomposition according to the following formula,1/TG(total)=w1/TG₍₁₎+w2/TG₍₂₎+w3/TG₍₃₎+optionally w4/TG₍₄₎+optionallyw5/TG₍₅₎+optionally wn/TG_((n)), with w1, w2, w3, w4, w5 and wn eachweight proportion of the monomer in the total mixture of the first andsecond monomers and optionally third monomers of 100% by weight, withn=6 to 50, wherein TG is greater than or equal to 100° C., and theviscosity of the composition at ambient room temperature (approx. 20° C.to 23° C.) is less than or equal to 3000 m·Pas.
 12. Polymerisedcomposition according to claim 1, wherein the (i) monomers are presentin the composition according to the following formula,1/TG(total)=w1/TG₍₁₎+w2/TG₍₂₎+w3/TG₍₃₎+optionally w4/TG₍₄₎+optionally5/TG₍₅₎+optionally wn/TG_((n)), with w1, w2, w3, w4, w5 and wn eachweight proportion of the monomer in the total mixture of the first andsecond monomers and optionally of the third monomer of 100% by weight,with n=6 to 50, wherein TG is greater than or equal to 100° C., and thepolymerised composition has a flexural strength of greater than or equalto 40 MPa (following DIN EN ISO 20795-2), measured in water at 55° C.,and/or b) an E modulus of greater than or equal to 800 MPa (followingDIN EN ISO 20795-2), measured in water at 55° C.
 13. Polymerisedcomposition according to claim 12, wherein the polymerised compositionhas, alternatively or cumulatively, i) a) a flexural strength of greaterthan or equal to 75 MPa (following DIN EN ISO 20795 2), and/or b) anE-modulus of greater than or equal to 2000 MPa (following DIN EN ISO20795-2), and/or ii) a) a flexural strength of greater than or equal to70 MPa (following DIN EN ISO 20795 2), measured in water at 37° C.,and/or b) an E-modulus of greater than or equal to 2000 MPa (followingDIN EN ISO 20795-2), measured in water at 37° C., and/or iii) a) aflexural strength of greater than or equal to 50 MPa (following DIN ENISO 20795 2), measured in water at 45° C., and/or b) an E-modulus ofgreater than or equal to 1500 MPa (following DIN EN ISO 20795-2),measured in water at 45° C., and/or iv) a) a flexural strength ofgreater than or equal to 40 MPa (following DIN EN ISO 20795 2), measuredin water at 55° C., and/or b) an E-modulus of greater than or equal to900 MPa (following DIN EN ISO 20795-2), measured in water at 55° C. 14.Blank in the form of a three-dimensional moulded body of a polymerisedcomposition according to claim 12 adapted for producing dentalprosthetic parts, orthopaedic appliances or dental pre-forms, whereinthe blank has a.1) a flexural strength of greater than or equal to 75MPa (following DIN EN ISO 20795-2), and/or b.1) an E-modulus of greaterthan or equal to 2000 MPa (following DIN EN ISO 20795 2), and optionallya.2) a flexural strength of greater than or equal to 50 MPa (followingDIN EN ISO 20795 2), measured in water at 45° C., and/or b.2) anE-modulus of greater than or equal to 1500 MPa (following DIN EN ISO20795 2), measured in water at 45° C.
 15. Method of using a compositionaccording to claim 1 for producing anatomical models, anatomicaltable-top models, dental working models, dental full models, dental diemodels, anatomical or dental saw-cut models, situation models,counter-bite models, functional models, Pre-models, repair models,precision models, anatomical models for replacement of the dentalplaster model of the dentition, aligners, dental splints, prostheticpars, dental prosthetic parts, orthopaedic appliances or dentalpre-forms.
 16. Method according to claim 15, wherein the dentalprosthetic parts comprise prosthesis base or parts thereof, artificialteeth, dental arch having at least two to 16 artificial teeth beinginterdentally connected in an integral manner, crowns, provisionalcrowns, total prostheses, total crowns, splints for orthodonticcorrections (similar to Invisalign), dental bridges, abutments,suprastructures, dental bars, inlays, onlays, orthopaedic appliances,such as occlusal splints, dental pre-forms of artificial teeth, surgicalguides for implantology, mouthguards, and/or implants.
 17. Compositionaccording to claim 4, wherein (i) in the composition are present 15 to25% by weight mono-functional acrylic esters based on a tricyclodecanealkanol, with alkanol comprising 1 to 6 C-atoms, and optionally 5 to 15%by weight diacrylic esters based on a tricyclodecane dialkanol, withalkanol comprising 1 to 6 C-atoms, wherein the total composition amountsto 100% by weight, or (ii) 5 to 15% by weight diacrylic ester beingbased on a tricyclodecane dialkanol, with alkanol comprising 1 to 6C-atoms, and 15 to 25% by weight mono-functional acrylic ester beingbased on a tricyclodecane alkanol, with alkanol comprising 1 to 6 Catoms, wherein the total composition amounts to 100% by weight, or (iii)15 to 45% by weight mixture comprising mono-functional acrylic esterbeing based on a tricyclodecane alkanol, with alkanol comprising 1 to 6C-atoms, and diacrylic ester being based on a tricyclodecane dialkanol,with alkanol comprising 1 to 6 C-atoms, wherein the total compositionamounts to 100% by weight.
 18. Method of using a composition accordingto claim 1, in a rapid prototyping or in a rapid manufacturing or rapidtooling method.